The invention relates to impact crushers, mills and similar machines in general, and more particularly to improvements in rotors which can be used in such machines to comminute coal, rock or other materials. Still more particularly, the invention relates to improvements in rotors which can be used with advantage in impact crushers or hammer mills.
It is known to assemble a rotor for use in an impact crusher or hammer mill from two or more metallic rotor discs which are welded to each other and have central portions or hubs serving to receive torque from a shaft. Neighboring discs are welded to
each other at their peripheries, i.e., radially outwardly of the respective hubs. Reference may be had, for example, to U.S. Pat. No. 3,098,614 and to German Utility Model No. 66 01 200. Welded seams are desirable and advantageous because they lend the necessary rigidity and stability to the assembled rotor.
A drawback of welded seams which are provided at the periphery of a conventional rotor for use in a hammer mill is that the seams are necessarily interrupted, i.e., such seams can be said to constitute relatively small portions of circumferentially complete annuli because they are interrupted in the regions of the hammers. The same holds true for the conventional rotors of impact crushers. In addition, the welding operation which involves bonding together two or more discs to form the rotor of an impact crusher takes up much time and is complex and expensive. A further drawback of conventional rotors for use in hammer mills or impact crushers is that their interrupted welded seams are located at the periphery and are thus subject to much wear and tear as a result of contact with material which is being comminuted.